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Full text of "ibm :: 3270 :: GA27-2871-2 3270 Information Display System Problem Determination Mar80"

GA27-2871-2 

File No. S360/S370/S3/4300/81 00-09 



Systems 



IBM 3270 

Information Display System 

Problem Determination 



IBM 3274 Control Units and Attached Terminals 



GA27-2871-2 

File No. S360/S370/S3/4300/81 00-09 



IBM 3270 

Information Display System 
Systems Problem Determination 



IBM 3274 Control Units and Attached Terminals 



Third Edition (March 1980) 

This edition (GA27-2871-2) obsoletes GA27-2871-1. Information concerning the IBM 
3279 Color Display Station, the IBM 3274 Model 5 1C, and the Network Problem 
Determination Application (NPDA) has been added, and the Error Codes in Appendix 
B have been updated. 

It is possible that this material may contain reference to, or information about, IBM 
products (machines and programs), programming, or services that are not announced 
in your country. Such references or information must not be construed to mean that 
IBM intends to announce such IBM products, programming, or services in your country. 

Copies of this and other IBM publications can be obtained through IBM branch offices. 

A form for readers' comments appears at the back of this publication. Address any 
additional comments concerning the contents of this publication to IBM Corporation, 
Department 52Q, Kingston, New York 12401. IBM may use or distribute any of the 
information you supply in any way it believes appropriate without incurring any 
obligation whatever. You may, of course, continue to use the information you supply. 

©Copyright International Business Machines Corporation 1978, 1980 



Preface 



The information contained in this publication is intended to 
assist customer personnel who are responsible for coordinat- 
ing problem determination activities on the IBM 3270 
Information Display System. 



Scope 

For the purposes of this publication, the IBM 3270 
Information Display System consists of an IBM 3274 
Control Unit with its attached IBM 3278 Display Stations, 
3279 Color Display Stations, IBM 3287 Printers, and/or 
3289 Line Printers. 

Problem determination procedures for an IBM 3270 
Information Display System that consists of an IBM 3276 
Control Unit Display Station with its attached terminals 
are described in the IBM 3270 Information Display System: 
System Problem Determination for 3276 Control Unit 
Display Stations, GA1 8-2042. 

Problem determination procedures for the IBM 3271 and 
3272 Control Units, IBM 3275 and 3277 Display Stations, 
and IBM 3284, 3286, and 3288 Printers are described in the 
IBM 3270 Information Display System: Problem Deter- 
mination Guide, GA27-2750, and are purposely omitted 
from this publication. 

This publication is not intended to replace the problem 
determination guides (PDGs) supplied with each unit of the 
3270 Information Display System, but is intended to 
supplement them by listing and coordinating the use of the 
problem determination facilities provided for the 3270 
Information Display System. 



Related Publications 

When appropriate, this publication refers to the unit PDGs, 
as well as other publications. The publications that may be 
required (depending upon your system configuration) are: 

IBM 3274 Control Unit Problem Determination Guide, 
GA27-2850 

IBM 3270 Information Display System: System Problem 
Determination for 3276 Control Unit Display Stations, 
GA 18-2042 

IBM 3278 Display Station Problem Determination Guide, 
GA27-2839 

IBM 3279 Color Display Station Problem Determination 
Guide, GA33-3051 

IBM 3287 Printer Problem Determination Guide, 

GA27-3151 

IBM 3289 Printer Problem Determination Guide, 
GA27-3141 

IBM 3270 Information Display System: Component 
Description, GA27-2749 

IBM 3270 Information Display System: 3274 Control 
Unit Planning and Setup Guide, GA27-2827 

3270 Facility Error Recognition System (FERS) Service 
Aid Description, G229-703 1 

OS I VS Display Exception Monitoring Facility (DEMFj 
User's Guide, GC34-2003 

Network Problem Determination Application Error 
Messages Manual, SC34-2012 

Network Problem Determination Application Terminal 
Use Guide, SC34-2013 

DOS/CICS User's Guide, G229-7030 

OS/CICS User's Guide, G229-7029 



Preface i 



Contents 



Chapter 1. Introduction 1-1 

Problem Determination Coordination 1-1 

Problem Determination Facilities 1-1 

Chapter 2. Problem Determination Overview 
Typical Approach 2-1 
Actions 2-3 



2-1 



Chapter 3. System Problem Determination Guide 3-1 

Check Display Station Operation with Control Unit 3-2 
Check Logical Connection between Display Station and 
Host System 3-6 

Chapter 4. Problem Determination Facilities Overview 4-1 
IBM 3278 Display Station and IBM 3279 Color 
Display Station 4-1 



IBM 3287 Printer and IBM 3289 Line Printer 4-1 
IBM 3274 Control Unit 4-1 
IBM 3270 Information Display System 4-2 
The Host System 4-3 

Appendix A. Status Summary Display A-l 

Appendix B. Status Indicator Codes B-l 

Glossary of Terms and Abbreviations G-l 

Index X-l 



Figures 



Figure 2-1. Possible System Configurations 2-2 

Figure B-l. 3274 Program Checks B-2 

Figure B-2. 3274 Communication Checks or Reminders 



B-6 



Contents iii 



Chapter 1. Introduction 

Problem determination procedures are performed by customer personnel to determine the 
probable location and cause of any problem that may appear on the IBM 3270 Informa- 
tion Display System. When the probable location and cause of the problem have been 
determined, the customer can then decide the following: 

• Is assistance required to resolve the problem? 

• Of whom should assistance be requested? 

• Where is assistance required? 

• Can useful work be accomplished while awaiting assistance? 

• Should assistance be scheduled on a deferred basis? 

Problem Determination Coordination 

Although the individual problem determination guides (PDGs) supplied with each unit of 
the 3270 Information Display System are useful for isolating a problem to those units or 
for eliminating those units as the probable source of the problem, the problem determina- 
tion activities should be coordinated on a system basis. A System Problem Determination 
Guide is provided in Chapter 3 of this publication to assist in this coordination. 

It is recommended that problem determination procedures performed on the 3270 
Information Display System be coordinated by designated personnel who are familiar with 
the problem determination concepts contained in this publication, with the problem 
determination facilities available on your system, and with the configuration of your 
system. 

Problem Determination Facilities 

To assist the customer in performing problem determination procedures on the 3270 
Information Display System and its associated communication facilities, certain facilities 
have been provided. These facilities are briefly described in Chapter 4 of this publication, 
with a reference to the appropriate publication for further details. 

Among the problem determination facilities that may be available at the host system are 
the Display Exception Monitoring Facility (DEMF), the Facility Error Recognition System 
(FERS), and the Network Problem Determination Application (NPDA). DEMF, FERS, 
and NPDA are network problem determination facilities, which are also briefly described 
in Chapter 4. 



Chapter 2. Problem Determination Overview 



Typical Approach 



Although a problem can occur at any point within the system, it is most likely to become 
apparent at one or more of the IBM 3270 terminals (3278, 3279, 3287, or 3289). To 
determine the probable location of the problem within the system, you must be familiar 
with the configuration of your system. 

Figure 2-1 shows possible system configurations and defines system levels at which problem 
determination may be performed. These levels are listed below in ascending sequence, 
starting with the lowest level: 

1. The 3270 terminal level. 

2. The 3270 Information Display System level, which, for problem determination 
purposes, amounts to the control unit level. 

3. The communication facility level. Although some tests may be initiated from the 
control unit or the host system, problem determination at this level should be 
coordinated at the host system. 

4. The host system level, which may have problem determination facilities that are 
applicable to all lower levels. 

To expedite problem determination, when a problem is detected at one level of the system, 
the problem should be reported to the coordinator at the next higher level. To minimize 
the impact on the system, problem determination should be done at the lowest level 
consistent with the symptoms. 

If DEMF, FERS, or NPDA is available on your host system, it might be advantageous to 
use that facility to determine the level at which to address the problem before attempting 
local problem determination procedures. The following procedure, however, is designed 
for most cases and starts at the terminal level. 



Determine which terminal types are affected by the problem. If 3278 or 3279 Display 
Stations are affected, determine the following: 

1. Do the affected display stations work properly when in offline mode? For a quick 
check, see if a cursor and a horizontal line across the screen are displayed. 

2. Can the affected display stations be made ready with respect to the control unit? 
For a quick check, see if a is displayed in the Operator Information Area. 

3. Are the display stations experiencing Machine Checks (X ^ nnn displayed in 
the Operator Information Area)? 

4. Are the display stations logically connected to the host system ( A. or J. displayed in 
the Operator Information Area)? 

5. Are the display stations experiencing Program Checks ( X PROGnnn displayed in 
the Operator Information Area)? 

6. Are the display stations experiencing Communications Checks ( X -Vz— nnn ) or 
Communication Reminders ( — Vz— nnn displayed in the Operator Information 
Area)? 



Chapter 2. Problem Determination Overview 2-1 




Communication ; 
Facility | 



8130/8140 
Processor 
* ii 



(Local) Direct 
Attached Loop 



Modem 



Modem 

wmmmmt 



S m ^ J 



Modem 



(Remote) Data Link 



I 



Local 



w 



X X 

7 T 



Modem 

mmmmmmmmmmf 



Modem 



3842 Loop 
Control Unit 



a 



Modem 



^ 



(Remote) 
Data Link 
Attached Loop 



(Remote) 
Data Link 



nil 



■4V 



_J 



I Remote Loop 



OR 



3270 Information Display System 



3274 (Except Model 51 C) 
Control Unit 



3278 or 3279 
Display Station 



Up to 31 



3278, 3279, 
3287, or 
3289 



Local Loop 



3274 Model 51 C 
Control Unit 



Up to 16 



3277, 3284, 
3286, 3287, 
3288 



3278 or 3279 
Display Station 



Up to 7 



3278, 3279, 
3287, or 
3289 



Up to 4 



3277, 3284, 
3286, 3287, 
3288 



Maximum of 32- 



-J> 



*^- 



Maximum of 8' 



-§^ 



•Maximum of 12 ■ 



-^>- 



Figure 2-1. Possible System Configurations 



2-2 



Actions 



If printers (3287 or 3289) are affected, determine the following: 

1. Have the printers been enabled by the control unit? 

2. Have the printers received an initial message from the control unit? 

3. Are the printers being polled by the control unit? 

In each of the preceding cases, it may be necessary to determine if more than one terminal 
attached to the same control unit is affected by the problem. If only one terminal is 
affected, it may be necessary to exchange device cables to determine if the control unit, 
device cable, or terminal is at fault. 

Caution: Do not connect or disconnect device cables during an electrical storm. Before 
cables are connected or disconnected, verify that the attached terminals are not being 
used. 

If the problem is not determined by the procedures in Chapter 3, the control unit problem 
determination procedure should be performed before assistance is requested. 



While performing problem determination procedures at any system level, you may be 
asked to perform some of the following actions: 

• Observe the symptoms 

• Retry the operation 

• Initiate and run tests, as requested 

• Record symptoms and test results 

• Report the results of problem determination, as prescribed by your management 

• Request assistance, as required 

In addition to the preceding actions, at certain system levels you may be asked to perform 
other actions, unique to that level. At the terminal or control unit level, you may be 
asked to swap device cables (see Figure 2-1). 

At the control unit level, you may be asked to test modems and to check cable connections 
at the modems. At the host system level, actions may be required to support problem 
determination on any part of the system, including the 3270 Information Display System 
and its communication facilities. As regards the 3270 Information Display System, host- 
system action may be required when a program check or communication check is detected 
at a 3270 terminal. 



Chapter 2. Problem Determination Overview 2-3 



Chapter 3. System Problem Determination Guide 

Start here 

• Was the problem reported at a 3278 or 3279 Display Station? 
YES NO 

• Was the problem reported at a 3287 Printer? 
YES NO 

The problem was reported at a 3289 Printer. 
Go to Q , page 3-12. 

Go to B|l , page 3-9. 

Is a cursor displayed at the failing display station? 
YES NO 

* A 

Go to ^m , page 3-4. 

i Is a horizontal line displayed across the screen at the failing display station? 
YES NO 

Go to 4fa , page 3-4. 

Press the upshift (A) key at a failing display station (if possible). 

° Is ft displayed in the Operator Information Area? 
YES NO 

Set the Normal/Test switch to the Test position, then to the Normal position. 
!. I 



• Is EJ displayed in the left portion of the Operator Information Area? 
YES NO 

I 

The display station is apparently not ready with respect to the control unit. Verify the symptoms on 
other failing display stations by operating the Normal/Test switch to the Test position, then back to 
the Normal position. 

• Is more than one display station (attached to the same control unit) failing with the same symptom? 

YES NO 



Go ton, page 3-4. 



Go to all page 3-3. 
Go to 0\ , page 3-2. 



Chapter 3. System Problem Determination Guide 3-1 



Check Display Station Operation with Control Unit 

© 

• Is X N nnn displayed in the Operator Information Area? 
YES NO 

Go to A , page 3-6. 

Set the Normal/Test switch to the Test position, then to the Normal position. 

Press the Reset key, record the symptoms on the appropriate Problem Report Form, and retry the failing operation. 
(See Note 2, page 3-3.) 

• Does the same failure occur? 
YES NO 

I 

End problem determination, and resume operation. 

• Is more than one display station (attached to the same control unit) failing? 
YES NO 

* A 

Go to ^p , page 3*4. 
Go to A , page 3-3. 



3-2 



o 



Caution: Do not connect or disconnect device cables during an electrical storm. 
Before cables are connected or disconnected, verify that the attached terminals 
are not being used. 

If device cables have been exchanged at the control unit ports and/or at the terminals, 
return them to their original connections. 

• If display stations were reconnected, set the Normal/Test switch to the Test position, 
then to the Normal position, at all reconnected display stations. 

• If the terminals affected were printers, press Reset and Test at 3287 Printers or press Reset 
at 3289 Printers. 

Perform problem determination on the control unit, using the 3274 Problem Determination 
Guide. 

Notes: 

1. Turning the 3274 Control Unit off and then on or initializing the 3274 affects all 
terminals attached to that 3274. 

2. Turning any terminal or control unit off and then on or initializing a control 
unit may affect its connection to the host system. It may be necessary to 
re-establish the connection to the host system or to log on to the host system 
when performing a reset, retry, and recovery operation. To prevent a 
system "hang" condition, the proper sequence must be used when turning 

a locally attached 3274 off or on. A locally attached 3274 has a 
Power/Interface rotary switch on its control panel. See the 3274 Control 
Unit Problem Determination Guide, GA27-2850. 



Chapter 3. System Problem Determination Guide 3-3 



o 

I 



Caution: Do not connect or disconnect device cables during an electrical storm. 
Before cables are connected or disconnected, verify that the attached terminals 
are not being used. 

If device cables have been exchanged at the control unit ports and/or at the terminals, 
return them to their original connections. 

If display stations were reconnected, set the Normal/Test switch to the Test position, 
then to the Normal position, at all reconnected display stations. 

Perform problem determination on the failing display station, using the 3278 or the 
3279 Problem Determination Guide. 

Press the Reset key, and retry the failing operation. (See Note 2, page 3-3.) 

• Has the problem been determined to be in the display station? 
YES NO 



Exchange the device cable from the failing display station with the device cable 
from a known working display station at the control unit ports. 

Set the Normal/Test switch to the Test position, then to the Normal position, 
at both display stations. 

Press the Reset key, and retry the failing operation. (See Note 2, page 3-3.) 

• Does the same display station fail? 
YES NO 



Go to ^^ , page 3-3. 

Go to ^S , page 3-5. 
Report the problem and resume operation. 



3-4 



© 

I 

Probable device cable or display station problem. 

Caution: Do not connect or disconnect device cables during an electrical storm. 
Before cables are connected or disconnected, verify that the attached terminals 
are not being used. 

Return the device cables to their original control unit ports. 

Set the Normal/Test switch to the Test position, then to the Normal position, at both display stations. 

• Is it possible to exchange the device cable at the failing display station with the device cable at a 
known working display station at the terminal end of the cables? 

YES NO 

i 

Probable device cable or display station problem. 

Ensure that all device cables are connected to their original connectors at both ends. 

Report the problem. 
Exchange device cables at the terminal ends. 

Set the Normal/Test switch to the Test position, then to the Normal position, at both display stations. 
Press the Reset key, and retry the failing operation. (See Note 2, page 3-3.) 

• Does the same display station fail? 
YES NO 

i 

Probable device cable failure. 

Return the device cables to their original connections. 

Set the Normal/Test switch to the Test position, then to the Normal position, at both display stations. 

Request assistance from the personnel responsible for device cables. 
Probable display station failure. 
Return the device cables to their original connections. 

Set the Normal/Test switch to the Test position, then to the Normal position, at both display stations. 
Report the problem. 



Chapter 3. System Problem Determination Guide 3-5 



Check Logical Connection between Display Station and Host System 

O 

• Is A. or J. displayed to the right of the @ in the Operator Information Area? 
YES NO 

I 

Inform the host system operator of the problem. 

• Is the host system operating without error and communicating with the failing 
3270 Information Display System? 

YES NO 



l 



When the host problem has been resolved, resume operation. 

• Is ! X PROGnnn displayed in the Operator Information Area? 
YES NO 



Go to (|s» , page 3-7. 



Press the Reset key, record the symptoms on the appropriate Problem Report Form, and retry the 
failing operation. (See Note 2, page 3-3.) 

• Does the operation still fail? 
YES NO 



End problem determination, and resume operation. 

Probable data stream problem from the host system. 

Record the sequences of the last keystrokes before the problem, if applicable. 

Report the problem to the host system support programmer for additional problem determination 
and recovery. 



3-6 



• Is X -Vz_nnn displayed in the Operator Information Area? 
YES NO 



• Is more than one display station (attached to the same control unit) failing? 

YES NO 



u.»,«. 



Go to (k9 , page 3-3. 

Press the Reset key, record the symptoms on the appropriate Problem Report Form, and 
retry the failing operation. (See Note 2, page 3-3.) 

• Does the operation still fail? 

YES NO 



End problem determination, and resume operation. 

Perform problem determination in the control unit PDG that relates to communication check ( X - 
problems. Refer to the page in the 3274 PDG entitled "Wrap Test". (See Notes 1 and 2, page 3-3.) 



* Is the problem determined to be in the control unit? 

YES NO 



Probable communication facility problem. 

• Is the host system on and operating without error? 
YES NO 



When the host system problem is resolved, resume operation. 
Go to @ , page 3-8. 
Go to fl-1 , page 3-3. 



jChapter 3. System Problem Determination Guide 3-7 



© 



© Is the Facility Error Recognition System (FERS), the Display Exception Monitoring Facility 

(DEMF), or the Network Problem Determination Application (NPDA) available? See Note. 
YES NO 

I 

Ensure that problem determination has been performed at the 3270 Information Display 
System (control unit, display station, and printer). 

• Was the problem isolated to the 3270 Display System? 
YES NO 

I 

Report the problem to the host system operator or to the Network Control Center for 
additional problem determination. 

Record the problem on the proper report form. 

Analyze the problem, using the following FERS, DEMF, or NPDA facilities: 

• Configuration data 

• Communication link statistics 

• Communication line statistics 

• Sense data 

• Status data 

For details, see the 3270 Facility Error Recognition System (FERS) Service Aid Description, G229-7031, 
the OS/VS Display Exception Monitoring Facility (DEMF) User's Guide, GC34-2003, or the Network 
Problem Determination Application (NPDA) Error Messages Manual, SC34-2012, and the Network 
Problem Determination Application (NPDA) Terminal Use Guide, SC34-2013. 

Note: 

To determine if FERS, DEMF, or NPDA is available on your host system, perform the following 
procedure: 

1. Clear the display screen, type in FERS, and press the ENTER key. The FERS menu will be 
displayed, if FERS is available. 

2. Clear the display screen, type in DEMF, and press the ENTER key. The DEMF menu will be 
displayed, if DEMF is available. 

3. If neither FERS nor DEMF is available, inquire from the Network Control Center or the host 
system operator if the Network Communications Control Facility (NCCF) and NPDA are 
available. If NPDA is available, request that it be invoked to perform problem determination 
for your terminal. 



3-8 



© 



• Is the CHECK light on? 

YES NO 



Ensure that the control unit is on and the device cable is connected to the control unit and to the printer. 

• Is the CU SIGNAL light on? 

YES NO 

l 

Either the control unit is not polling the printer or there is a device cable problem. 

Caution: Do not connect or disconnect device cables during an electrical storm. 
Before cables are connected or disconnected, verify that the attached terminals 
are not being used. 

If there is a known working printer attached to the control unit, exchange the device cable 
to the working printer with the device cable to the failing printer at the control unit ports. 

Note: At the 3274 Control Unit, do not exchange a device cable from an A port with one 
from a B port. 

At the failing printer: 

1 . Press and hold the Test switch. 

2. Press and release the Reset switch. 

3. Release the Test switch. 

° Is the CU SIGNAL light on after the internal tests run? 
YES NO 



Go to f» , page 3-1 1 , 



Go to ^ffl , page 3-3. 

At the failing printer: 

1 . Press and hold the Test switch. 

2. Press and release the Reset switch. 

3. Release the Test switch. 

• Is the READY light on after the internal tests run? 

YES NO 



Go to HB, page 3-10. 



Goto A, page 3-10. 
Perform problem determination on the failing printer, using the 3287 Problem Determination Guide. 



Chapter 3. System Problem Determination Guide 3-9 



o o o 



To print out the PC1 A storage area: 

1 . Press and hold the Test switch. 

2. Press and release the Form Feed switch. 

3. Release the Test switch. 

• Does AA3274AA print out for storage addresses 004A through 004D? 
YES NO 



I. 

Go to 



Q,th 



is page. 



the printer is connected to, is enabled by, and has received a message from the control unit. 

• Is a printer failing during a host-initiated print operation? 

YES NO 



The printer is failing during a local copy operation. 
Request assistance at the control unit location. 



Report the problem to the host system operator. 

Perform problem determination on the failing printer, using the 3289 or 3287 Problem Determination Guide. 

• Was the problem determined? 
YES NO 

I 

Perform problem determination on the control unit, using the 3274 Problem Determination Guide. 



• Was the problem determined? 
YES NO 



Request assistance. 



Resume operation. 

Request assistance if required. 



3-10 



o 

L 



ution: Do not connect or disconnect device cables during an electrical storm. 
Before cables are connected or disconnected, verify that the attached terminals 
are not being used. 

Return device cables to their original control unit ports. 

At the reconnected printers: 

1 . Press and hold the Test switch. 

2. Press and release the Reset switch. 

3. Release the Test switch. 

• Is it possible to exchange the device cable at the failing printer with the device cable at a known 

working printer at the printer end of the cable? 
YES NO 



Probable cable or printer problem. 

Report the problem. 

Exchange the device cable from the failing printer with the device cable from a known working printer 
at the printer end of the cable. 

At the failing printer: 

1 . Press and hold the Test switch. 

2. Press and release the Reset switch. 

3. Release the Test switch. 

• Is the CU SIGNAL light on after the internal tests run? 
YES NO 

I 

Probable 3287 Printer problem. 

Return the device cables to their original connections. 

At the reconnected printers: 

1 . Press and hold the Test switch. 

2. Press and release the Reset switch. 

3. Release the Test switch. 

Report the problem, and request assistance. 

Probable device cable problem. 

Return the device cables to their original connections. 

At the reconnected printers: 

1 . Press and hold the Test switch. 

2. Press and release the Reset switch. 

3. Release the Test switch. 

Request assistance from the personnel responsible for device cables. 



Chapter 3. System Problem Determination Guide 3-11 



• Is the CHECK light on? 

YES NO 



• Is the READY light on? 

YES NO 



Press the Enable Print switch. 

Press the Reset switch. 

• Is the READY light on after the internal tests have run? 
YES NO 

I 

o Is there another 3289 Printer, attached to the same control unit, 
that is working properly? 

YES NO 



Goto #B, page 3-10. 



Goto 5JJ, page 3-13. 

Print "Short Memory" via the Print Dump Routine, as follows: 

1 . Press the Hold Print switch. 

2. Set Selector switch to 70. 

3. Press the Code switch. 

o Does AA3274AA print out for storage addresses 004A through 004D? 
YES NO 



• Is there another 3289 Printer, attached to the same control unit, that is 

working properly? 
YES NO 



Go to fgr, , page 3-10. 
Go to fife , page 3-13. 



Go to (Jig), page 3-10. 
Perform problem determination on the failing printer, using the 3289 Problem Determination Guide. 



•3-12 



© 



Caution: Do not connect or disconnect device cables during an electrical storm. 
Before cables are connected or disconnected, verify that the attached terminals 
are not being used. 

Exchange the device cable from the failing printer with the device cable from a known 
working printer at the control unit ports. 

Note: At the 3274 Control Unit, do not exchange a device cable from an A port with one 
from a B port. 

At the failing printer: 

1 . Press the Enable Print switch. 

2. Press the Reset switch. 

• Is the READY light on after the internal tests run? 
YES NO 



Device cable or printer problem. 

Return the device cables to their original control unit ports. 

At both reconnected printers: 

1 . Press the Enable Print switch. 

2. Press the Reset switch. 

• Is it possible to exchange the device cable at the failing printer with the device cable 

at a known working printer at the terminal end of the cables? 
YES NO 

I 

Probable device cable or printer problem. 
Report the problem, and request assistance. 



Goto © > page 3-14. 
Go to ^3 , page 3-3. 



Chapter 3. System Problem Determination Guide 3-13 



© 



Exchange the device cable at the failing printer with the device cable from a known working printer 
at the printer end of the cable. 

Note: Do not exchange device cables between a 3289 and a B type printer (3284, 3286, and 3288). 

At the failing printer: 

1 . Press the Enable Print switch. 

2. Press the Reset switch. 

• Is the READY light on after the internal tests have run? 
YES NO 



Probable printer problem. 

Return the device cables to their original connections. 

At both reconnected printers: 

1 . Press the Enable Print switch. 

2. Press the Reset switch. 

Report the problem, and request assistance. 

Probable device cable problem. 

Return the device cables to their original connections. 

At both reconnected printers: 

1 . Press the Enable Print switch. 

2. Press the Reset switch . 

Request assistance from the personnel responsible for device cables. 



3-14 



Chapter 4. Problem Determination Facilities Overview 



Each level of the system has associated problem determination facilities that are used to 
isolate 3270 type failures within the system. Some of these facilities are used concurrently 
with the operation of other system elements at that level and require only the dedicated 
resource being tested. An example of these facilities is the concurrent test contained in 
the 3270 control units, which is required to test the features of the 3278 Display Station. 
Other facilities are used offline and require dedicated use of all the resources affected. An 
example of these facilities is the basic assurance test contained in the 3270 control units. 
The facilities are listed by the 3270 unit and system level to which they apply. 

IBM 3278 Display Station and IBM 3279 Color 
Display Station 

The IBM 3278 Display Station and the IBM 3279 Color Display Station and their 
keyboards can be tested offline from the control unit. The facilities are: 

• A display character check of the character set. Analysis of this test can determine if 
the proper characters are interpreted in the display station and if every character 
position on the display screen is usable. 

• A keyboard check that displays a character representative of each keyboard key, except 
the RESET (control) key, that is pressed. 

• Lights that indicate the readiness status of the display station. 

• Controls that determine if the status is on/off or test and that control the display 
screen brightness of the display station. The selector light-pen, color, programmed 
symbols, and other features can be tested via concurrent tests resident in the control 
unit. 

See the IBM 3278 Display Station Problem Determination Guide, GA27-2839, and the 
IBM 3279 Color Display Station Problem Determination Guide, GA33-3051, for details on 
the use of these facilities. 

IBM 3287 Printer and IBM 3289 Line Printer 

The problem determination facilities in the IBM 3287 Printer and the IBM 3289 Line 
Printer are basically the same. The details concerning the operation of these facilities are 
contained in the IBM 3287 Printer Problem Determination Guide, GA27-3 151, and 
IBM 3289 Printer Problem Determination Guide, GA27-3 14 1 . 

The facilities are: 

• Lights that indicate the readiness status, error check status, test status, and control unit 
connection status of the printer. 

• Lights that define the conditions causing the error status, and the operational status of 
the printer. 

• Switches that control the on/off status, test status, and buffer print status of the printer. 

• Tests that automatically test the printer and initialize it for operation. 



IBM 3274 Control Unit 



The IBM 3274 Control Unit is the nucleus of the 3270 Information Display System, of 
which it is a part. Its problem determination facilities are used to test and isolate the con- 
trol unit within the 3270 Information Display System and to isolate the 3270 Information 
Display System from the remainder of the system. The use of these facilities normally 

Chapter 4. Problem Determination Facilities Overview 4-1 



affects the entire 3270 Information Display System; therefore, they should be used only 
when the 3274 Control Unit is suspected of failing. 

The facilities are: 

• A basic test that verifies that the base control unit is functioning properly. This test is 
run automatically when power is turned on; or it can be initiated by pressing the IML 
pushbutton (without pressing the Alt IML Address switch). 

• A remote interface test that is run as part of the basic test, or separately, by pressing 
the IML pushbutton while holding the Alt IML Address switch in the 2 position. 
This applies only to remotely attached 3274 Control Units. 

• Lights that indicate test-failure status during the IML process or retry status during the 
operational state. 

• A light that indicates the local/remote power status of the control unit. 

• A Power/Interface switch that selects the online/offline status of the power.. This 
switch is present only on locally attached 3274 Control Units. 

See the IBM 3274 Control Unit Problem Determination Guide, GA27-2850, for details on 
the use of these facilities. 

IBM 3270 Information Display System 

For the purposes of this publication, the IBM 3270 Information Display System consists 
of the IBM 3274 Control Unit and its attached IBM 3278 and 3279 Display Stations, 
3287 Printers, and 3289 Printers. 

Facilities exist in the control unit to determine if the problem is internal or external to the 
3270 Information Display System. If the problem appears to be internal to the 3270 
Information Display System, these facilities are also used to determine which unit, within 
the 3270 Information Display System, is the probable cause of the problem. 

The facilities are as follows: 

• Concurrent tests are available that test the path from the control unit to the attached 
terminals and provide a test pattern which allows testing the 3278 and 3279 Display 
Station features. 

These tests can be initiated from any display station with a keyboard, to itself or to any 
other display station within the 3270 Information Display System, concurrently with 
the normal operation of the 3270 Information Display System. Caution should be 
exercised when testing another terminal to ensure that the terminal to be tested is 
available for test. 

• A test is available that displays the trouble status of all attached terminals within the 

3 270 Information Display System. (See Appendix A.) This test can be initiated from 
a 3278 or 3279 keyboard and is run concurrently with other 3270 Information Display 
System operations. 

• A test message is available at the 3287 or 3289 Printer immediately after the printer 
is turned on (provided the control unit is on). To minimize the overprinting of usable 
information when the printer is functioning online, this message can be printed only 
when the printer is in test status. 

• The physical locations for attaching the device cables to the control unit are readily 
accessible. The connectors contained in this area do not require the use of tools or ' 
special equipment to connect or disconnect. See the IBM 3270 Information Display 
System: 3274 Control Unit Planning and Setup Guide, GA27-2827. This permits the 
interchanging of device cables at the ports to determine if the problem exists in the 
terminal or in the control unit. 

4-2 



The Host System 



Caution: Do not connect or disconnect the device cables during an electrical storm. 
Before cables are connected or disconnected, verify that the attached terminals are not 
being used. 

• Interface wrap tests are available for testing the link when the 3274 is remotely attached. 
This test interrupts the operation of all attached terminals; therefore, it should be per- 
formed only when the entire 3270 Information Display System is apparently failing or 
when symptoms indicate that the problem is in the communication facility, external to 
the 3270 Information Display System. 

• Three check condition symbols ( ^ — *vz_ , and PROG ) and their respective 
numeric codes are displayed in the Operator Information Area of the 3278 or 3279 
Display Station. The symbol is used to define the major problem category, and the 
numeric code is used to further define the problem. See Appendix B for the signifi- 
cance of the — Vz— and PROG symbols and codes. 

• There are also functional symbols that indicate the readiness status, the host attachment 
status, and operator activity, displayed in the Operator Information Area of the 3278 
or 3279 Display Station. 

• The 3274 Control Unit has lights that indicate if the problem is probably internal or 
external to the control unit. 



The host system consists of the central processing unit (CPU), the channel, and the com- 
munication controller or transmission control unit. Communication facilities connect the 
host system to attached terminals or subsystems, including the 3270 Information Display 
System. An example of possible system configurations is illustrated in Figure 2-1. 

A facility may reside in the host system that can be used for problem determination to 
the suspected 3270 Information Display System. This facility can be initiated from the 
suspected 3270 Information Display System or from other elements of the same system. 

• The 3270 Information Display System error statistics and transmission line error 
statistics are logged at the host system through the Facility Error Recognition System 
(FERS) facility. The retrieval of this data through the FERS facility permits problem 
determination to the suspected 3270 Information Display System. 

When a nonrecoverable error occurs, it is logged at the host system. The data is 
retrieved through the display stations and can be displayed in various formats, as 
follows: 

— A summary of errors by nonswitched line or line groups 

— A summary of errors by 3270 control unit on the specified line 

— A summary of errors by attached terminal on the specified 3270 control unit and a 
count of 3270 control unit errors, not related to any terminal 

— A summary of errors on a specified terminal in chronological order 

— Additional data describing an error 

— Channel status word (CSW) and/or sense bit combinations 

See the 3270 Facility Error Recognition System (FERS) Service Aid Description, 
G229-7031, the DOS/CICS User's Guide, G229-7030, and the OS/CICS User's Guide, 
G229-7029, for configuration, implementation, and operation information. 



Chapter 4. Problem Determination Facilities Overview 4-3 



• Display Exception Monitoring Facility (DEMF) is a problem determination tool that is 
used in isolating problems within a communications network. The process progressively 
points to each most probable failing component (a line, a control unit, or a terminal). 
User-oriented images of permanent error counts for all lines, selected lines, control units, 
and terminals are helpful in determining the location of the problem. Exceptional 
status conditions, and their interpretations, are provided at the terminal level to aid in 
determining the most probable cause of the problem. 

This data is presented as: 

— Error counts for remote or local 3270 control units 

— Error counts for all 3270 control units for the specified line, and/or all line errors 
for the specified line 

— Error counts, by attached terminal, for the specified 3270 control unit 

— A status description, in chronological order, of specific line or terminal errors 

— An explanation of the selected error for the terminal 

— A list of possible causes for various combinations of 3270 sense and status 
conditions 

Refer to the OS/VS Display Exception Monitoring Facility User's Guide, GC34-2003, 
for details concerning the required software configuration, communication facility, and 
operating procedures. 

• Network Problem Determination Application (NPDA) facilities permit recording, 
retrieval, and display of statistical data from the 3274 Control Unit. The data is 
presented as: 

— Communication link test statistics 

— Statistical counts of communication errors, machine errors, and SNA protocol 
errors 

— Engineering change information relative to the 3274 Control Unit 

Refer to the Network Problem Determination Application Terminal Use Guide, 
SC34-2013, and the Network Problem Determination Application Error Messages 
Manual, SC34-2012, for software configuration, communication, and operating 
procedures. 

If DEMF, FERS, or NPDA is available in your system, it can be accessed by any 3270 
terminal. An operator can request data about his own terminal or about any other 
terminal in the network. An operator can ask for a specific terminal's error data or step 
through the higher levels (for example, line, control unit) of error information before 
narrowing the search to a suspected terminal. DEMF, FERS, or NPDA could be all that 
is required for problem determination. 



44 



Appendix A. Status Summary Display 



Status Summary Display is a concurrent-test facility that displays the availability status of 
each terminal relative to a specific control unit. 

The test is invoked from any IBM 3278 or 3279 Display Station with keyboard by the 
following sequence: 

1. Depress the ALT and TEST keys. 

2. Type in /3. 

3. Press the ENTER key. 

If the requesting terminal is a 3278 or 3279 Display Station attached to a 3274 Control 
Unit, the response image displayed is: 

Line 1: 012345678901. ..N 

Line 2: 1, 0, or a — (under each position in line 1) 

Line 3: Subsystem statistics (not applicable for problem determination) 

Where: 

line 1 = digits representing the low-order digit of the port address per the configura- 
tion for that control unit. (Example: 16 ports appear as 12 3 4 5 6 7 
8 9 12 3 4 5). Blanks may appear, separating A type ports from B 
type ports. 

Line 2 = terminal status, where : 

1 = terminal powered on with no control-unit-detected errors 

= terminal powered off or device cable detached 

— = terminal disabled because of errors detected bv the control unit. 



Appendix A. Status Summary Display A-l 



Appendix B. Status Indicator Codes 



Described in this appendix are two categories of check condition symbols (and a 
reminder symbol) that are followed by a numeric code and displayed in the Operator 
Information Area on the 3278 or 3279 display screen. The symbol defines a major prob- 
lem category, and the numeric code further defines the problem. The symbols are: 

X PROG Program Check. This symbol is displayed when a programming error 
is detected in the data received by the control unit. 

X _ n vz _ Communication Check. This symbol is displayed when a communication 
link error is detected, indicating that data cannot be sent. The communi- 
cation reminder symbol ( — Vz_ ) is displayed as long as the condition 
that caused the problem exists. 

The numeric codes, which follow these symbols, consist of three digits. (The 3274 Control 
Unit is identified by the @ symbol, displayed in the Readiness location of the Operator 
Information Area.) 

The numeric codes are defined in Figures B-l and B-2. These codes and their meanings 
are subject to change from time to time. This information, therefore, may not always 
be up to date. If there is any doubt, the corresponding material in the latest version of 
the 3270 Information Display System: Component Description, GA27-2749, should be 
considered the final authority. 



Appendix B. Status Indicator Codes B-l 



Error Code 


Indicator 


Probable Cause 


Effect 


Recovery 


401 

(All 3274 Models) 


ProgChk 


Invalid command 
received. 


Display error indicator on 
affected 3278/3279. 
Set sense: 

Non-SNA: CR 

SNA: 1003 


Press RESET to reset the program 
check indicator, and retry the 
operation. Call host-support 
programmer if the problem 
persists, because it is probably a 
data stream error. 


402 

(Model 1A) 
(Model 1C) 
(Model 51 C) 
(Model 1D) 


Prog Chk 


Invalid (out-of-range) 
address has been 
received following an 
SBA, RA, or EUA 
order. 


Display error indicator on 
affected 3278/3279. 
Set sense: 

Non-SNA: OC. 

SNA: 1005 


403 

(Model 1A) 
(Model 1C) 
(Model 51C) 
(Model 1D) 


Prog Chk 


Data stream containing 
data following a Rd, 
RdMod,orEAU 
command was received. 


Display error indicator on 
affected 3278/3279. 
Set sense: 

Non-SNA: OC 

SNA: 1003 


404 

(Model 1A) 
(Model 1C) 
(Model 51 C) 
(Model 1D) 


Prog Chk 


Data stream ended 
before all required 
bytes of an SBA, RA, 
EUA, or SF order 
sequence were received. 


Display error indicator on 
affected 3278/3279. 
Set sense: 

Non-SNA: OC 

SNA: 1005 


405 

(Model 1 C-BSC) 

(Model 51 C-BSC) 


Prog Chk 


Invalid Copy command 
was received. 


Display error indicator on 
affected 3278/3279. 
Set sense: OC 


406 

(Model 1 C-BSC) 
(Model 51 C-BSC) 
(Model 1D) 


Prog Chk 


Invalid command 
sequence received. 


407 
(Model 1B) 


Prog Chk 


Valid command or 
order received that 
cannot be executed 
because: 

a. SBA, RA, or EUA 
order specifies an 
invalid address, or 

b. Write data stream 
ends before all 
required bytes of 
SBA, RA, EUA, or 
SF order sequence 
are received, or 

c. Write, E/W, or 
EWA with Start 
Print bit set in 
WCC is chained to 
the next command; 
the print operation 
is suppressed. 


408 

(Model 1 C-BSC) 

(Model 51 C-BSC) 


Prog Chk 


Line buffer overflow. 


410 

(Model 1A) 


Prog Chk 


RU greater than 1536 
bytes received. 


Display error indicator on 
affected 3278/3279. 
Set sense: 1002 



Figure B-l (Part 1 of 4). 3274 Program Checks 



B-2 



Error Code 


Indicator 


Probable Cause 


Effect 


Recovery 


411 


Prog Chk 


LU1 RU received with 


Display error indicator on 


Press RESET to reset the program 


(SNA) 




greater length than in 


affected 3278/3279. 


check indicator, and retry the 






BIND specification. 


Set sense: 1002 


operation. Call host-support 
programmer if the problem 
persists, because it is probably a 
data stream error. 


413 
(SNA) 


Prog Chk 


The attempted func- 
tion is not supported. 


Display error indicator on 
affected 3278/3279. 








Set sense: 1003 




414 


Prog Chk 


A bad pool count or a 


(Encrypt/Decrypt) 




non-module-8 RU has 
been received during 
a cryptographic session. 






420 


Prog Chk 


LIC carried exception 


Display error indicator on 


(SNA) 




response when BIND 
specified definite 
response. 


affected 3278/3279. 
Set sense: 4006 




421 


Prog Chk 


LIC carried definite 


Display error indicator on 


(SNA) 




response when BIND 
specified exception 
response. 


affected 3278/3279. 
Set sense: 4007 




422 


Prog Chk 


No Response is not 


Display error indicator on 


(SNA) 




allowed. 


affected 3278/3279. 
Set sense: 400A 




423 


Prog Chk 


Format indicator (F) 


Display error indicator on 


(SNA) 




bit is not allowed. 


affected 3278/3279. 
Set sense: 400F 




430 


Prog Chk 


Sequence number 


Display error indicator on 


(SNA) 




error. 


affected 3278/3279. 
Set sense: 2001 




431 


Prog Chk 


Chaining error. 


Display error indicator on 


(SNA) 






affected 3278/3279. 
Set sense: 2002 




432 


Prog Chk 


Bracket error. 


Display error indicator on 


(SNA) 






affected 3278/3279. 
Set sense: 2003 




433 


Prog Chk 


Data Traffic Reset. 


Display error indicator on 


(SNA) 






affected 3278/3279. 
Set sense: 2005 




434 


Prog Chk 


Direction error. 


Display error indicator on 


(SNA) 






affected 3278/3279. 
Set sense: 2004 




439 


Prog Chk 


FM data received prior 


Display error indicator on 


(Encrypt/Decrypt) 




to a valid CRV. 


affected 3278/3279. 
Set sense: 1001 




442 


Prog Chk 


Request not 


Display error indicator on 


(SNA) 




executable. 


affected 3278/3279. 
Set sense: 081 C 




443 


Prog Chk 


Change Direction 


Display error indicator on 


(SNA) 




required. 


affected 3278/3279. 
Set sense: 0829 





Figure B-l (Part 2 of 4). 3274 Program Checks 



Appendix B. Status Indicator Codes B-3 



Error Code 


Indicator 


Probable Cause 


Effect 


Recovery 


445 


ProgChk 


ACTLU not valid. 


Display error indicator on 


Press RESET to reset the program 


(SNA) 






affected 3278/3279. 
Set sense: 0821 


check indicator, and retry the 
operation. Call host-support 


450-458 
(SNA) 


Prog Chk 


BIND Reject: BIND 
parameters do not 
match BIND checks: 

a. 450=Profile error 

b. 451=Primary 
protocol error 

c. 452=Secondary 
protocol error 

d. 453=Common 
protocol error 

e. 454=Screen Size 
specification error 

f. 455=LU profile 
error 

g. 456=LU1 error 
h. 457=BINDSpec 

for crypto was 
specified when 
feature not present 
or a CRV was 
received in CRV- 
invalid state 
i. 458=Crypto Master 
Key mismatch be- 
tween the host and 
the control unit. 
See Planning and 
Setup Guide 




programmer if the problem 
persists, because it is probably a 
data stream error. 


460 


Prog Chk 


Control unit detected 


Display error indicator on 






an invalid printer 


the 3278/3279 on port 0. 








authorization matrix. 






470 


ProgChk 


An unsupported order 


Display error indicator on 


(Extended 3270 




was detected in the 


affected 3278/3279. 




Data Stream) 




data stream. 


Set sense: 
Non-SNA: OC 
SNA: 1003 




471 

(Extended 3270 


ProgChk 


Extended 3270 data 
stream function cannot 




Data Stream) 




be executed because 
of: 

a. Unsupported 
structured field 
type. 

b. Device without 
ECSA feature. 

c. Invalid load format 
addressed to PS 
buffer. 

d. Invalid X or Y 
value for Load PS 
structured field. 

e. Specified color 
plane outside of 
supported range. 







Figure B-l (Part 3 of 4). 3274 Program Checks 



B4 



Error Code 


Indicator 


Probable Cause 


Effect 


Recovery 


471 (continued) 


Prog Chk 


f. Specified PS Buffer 


Display error indicator on 


Press RESET to reset the program 






outside of supported 


affected 3278/3279. 


check indicator, and retry the 






range. 


Set sense: 


operation. Call host-support 






g. Section ID not 


Non-SNA: OC 


programmer if the problem 






supported (Byte H 


SNA: 1005 


persists, because it is probably a 






not = 0). 




data stream error. 






h. Invalid length 










structured field. 










i. Invalid partition ID. 










j. Invalid Mode in Set 










Reply Mode. 










k. Invalid operation in 










Read Partition (not 










Query). 










I. Alias out of valid 










range. 










m. Invalid EBCDIC 










code point. 










n. Invalid reserved bits 










were received in the 










data stream. 






472 


ProgChk 


Improper command 


Display error indicator on 


(Extended 3270 




sequence from host, 


affected 3278/3279. 




Data Stream) 




caused by a Read 
Structured Field 
state error. 


Set sense: 
Non-SNA: OC 
SNA: 0871 




473 


Prog Chk 


a. ECSA adapter pre- 


Display error indicator on 


(Extended 3270 




sent but a PS buffer 


affected 3278/3279. 




Data Stream) 




was addressed that 
was not physically 
present, 
b. A color plane 
operation was 
attempted to a 
buffer with no 
color plane. 


Set sense: 
Non-SNA: OC 
SNA: 084C 




474 


Prog Chk 


No extended DCB 


The device cannot be used for 


Logon for an application that does 


(Extended 3270 




customized for this 


execution of extended data 


not require extended data stream 


Data Stream) 




device. 


stream functions. Display 
error indicator on affected 
3278/3279. 
Set sense: 

Non-SNA: OC 

SNA: 1003 


function, or; 

Perform the customizing procedure 
for the extended DCB for this 
device and re-IML. 


498 


ProgChk 


Negative response 


Display error indicator on 


Press RESET to reset the program 


(SNA) 




received. 


affected 3278/3279. 


check indicator, and retry the 
operation. Call host-support 










499 


Prog Chk 


Exception request. 




programmer if the problem 


(SNA) 








persists, because it is probably a 
data stream error. 



Figure B-l (Part 4 of 4). 3274 Program Checks 



Appendix B. Status Indicator Codes B-S 



Error Code 


Indicator 


Probable Cause 


Effect 


Recovery 


501 

(Model 1C) 
(Model 51C) 


Comm Chk 

or 
Reminder 


Data Set Ready (DSR) 
signal from modem . 
has dropped. 


Display error indicator on all 
3278s/3279s. Host commun- 
ication is inhibited. 


Check modem. Press RESET, and 
retry the operation. 


501 

(Model 1 A) 
(Model 1B) 
(Model 1D) 


Comm Chk 

or 
Reminder 


Manual OFFLINE 
switch in the 
OFFLINE position. 


At the control unit, place switch 
in the ONLINE position. 


501 

(Model 51C; Multi- 
Use Comm Loop) 


Comm Chk 

or 
Reminder 


Local /Comm switch 
set to Local. 


Host communication is 
inhibited. 


At the CU, switch the Local/Comm 
switch to Comm. 


502 

(Model 1C-SDLC) 

(Model 51 C-SDLC) 


Comm Chk 

or 
Reminder 


Clear to Send (CTS) 
signal from the modem 
is missing. 


Display error indicator on all 
3278s/3279s. Host commun- 
ication is inhibited. 


Check modem. Press RESET, and 
retry the operation. 


503 

(Model 1B) 
(Model 1D) 


Comm Chk 

or 
Reminder 


A selective reset 
sequence was received. 


Press RESET, and retry the 
operation. 


504 

(Model 1C-SDLC) 

(Model 51C-SDLC) 


Comm Chk 

or 
Reminder 


On a switched network, 
a DISC has been 
received. 


Display error indicator on all 
affected 3278s/3279s. The 
station is closed and discon- 
nected. 


A new call sequence is required. 


505 

(Model 1 C-SDLC) 

(Model 51 C-SDLC) 


Comm Chk 

or 
Reminder 


Initial state of CU, or a 
Disconnect command 
was received. 


Display error indicator on all 
3278s/3279s. Host commun- 
ication is inhibited. 


Host recovery. (An SNRM com- 
mand is required.) Press RESET, 
and retry the operation. 


505 
(Model 1A) 


Comm Chk 

or 
Reminder 


Initial state of CU, a 
Disconnect command, 
or a System Reset was 
received. 


Host recovery. (A connect 
sequence is required.) Press 
RESET, and retry the operation. 


505 

(Model 1B) 
(Model 1D) 


Comm Chk 

or 
Reminder 


System Reset was 
received. 


Display error indicator on all 
3278s/3279s. 


Host recovery. (The first I/O 
operation, other than TIO or 
Sense, will clear the Communica- 
tion Reminder.) Press RESET, 
and retry the operation. 


505 

(Model 51 C; Multi- 
Use Comm Loop) 


Comm Chk 

or 
Reminder 


Initial state of control 
unit; a DISC command 
has been received, or 
beaconning has been 
completed. 


Display error indicator on all 
3278s/3279s. Host commun- 
ication is inhibited. 


Host recovery. (An SNRM com- 
mand is required.) Press RESET 
and retry the operation. 


507 

(Model 51 C; Multi- 
Use Comm Loop) 


Comm Chk 

or 
Reminder 


No carrier for a 
4-second period. 


Display error indicator on all 
3278s/3279s. The station is 
closed and wrap tests are 
performed. If the wrap tests 
are successful, beaconning is 
initiated and— Vz_ 51 5 is 
broadcast. 


■ • i, V r-rt-i 


Host recovery. If ^z 507 

remains in the reminder area, 
check for an X^l 3nn indicator 
and refer to the description of 
that error condition. 


508 

(Model 51 C; Multi- 
Use Comm Loop) 


Comm Chk 

or 
Reminder 


A CNFG command was 
received that specified 
Set Monitor Mode. 


Display error indicator on all 
3278s/3279s. Monitor Mode 
is entered. 


A CNFG command that specifies 
CLEAR or RESET is required 
from the host. 


509 

(Model 51C; Multi- 
Use Comm Loop) 


Comm Chk 

or 
Reminder 


A CNFG command was 
received that specified 
Suppress Loop Carrier 
Mode. 


Display error indicator on all 
3278s/3279s. The controller 
suppresses the carrier after 
responding to the CNFG 
command. 



Figure B-2 (Part 1 of 4). 3274 Communication Checks or Reminders 
B-6 



Error Code 


Indicator 


Probable Cause 


Effect 


Recovery 


510 


Comm Chk 


The PU is not active. 


Display error indicator on all 


Host recovery. (ACTPU is 


(SNA) 


or 
Reminder 




3278s/3279s. 


required.) 


511 


Comm Chk 


Disconnect command 


Host recovery. (Connect is 


(Model 1A) 


or 
Reminder 


was received when PU 
was active. 




required.) 


512 


Comm Chk 


Connect command was 


Host recovery. (ACTPU is 


(Model 1A) 


or 
Reminder 


received when PU was 
already connected. 




required.) 


514 


Comm Chk 


Connect error caused 


Host recovery. (Valid Connect is 


(Model 1A) 


or 
Reminder 


by: 

a. Odd number buffer 
length was speci- 
fied, or 

b. Insufficient length 
buffer was speci- 
fied. 




required.) 


515 


Comm Chk 


While monitoring 


Beaconning mode is entered 


Receipt of more than 50% carrier 


(Model 51 C; Multi- 


or 


carrier, a No-carrier 


and carrier is sampled. 


samples will cause the station to 


Use Comm Loop) 


Reminder 


condition was detect- 
ed and wrap tests were 
successfully run. 




stop beaconning. Carrier is 
required (see 505). 


518 


Comm Chk 


A segment was received 


Display error indicator on all 


Host recovery. (SNRM is 


(Model 1C-SDLC) 


or 


with improper 


3278s/3279s;allPUsand 


required.) 


(Model 51 C-SDLC) 


Reminder 


sequencing in the TH 
MPF bits. 


LUs are deactivated. 




519 


Comm Chk 


A message was received 


CCA: SDLC Command Reject 


Host recovery. (Check NCP 


(Model 1 C-SDLC) 


or 


that is larger than the 


response is sent to host. 


Sysgen parameters if the condition 


(Model 51 C-SDLC) 


Reminder 


CU buffer. 


HPCA: NR/NS mismatch 


persists.) 


520 


Comm Chk 


Nonproductive timeout 


Display error indicator on all 


Verify the operational status of the 


(Model 1 C-SDLC) 


or 


caused by: 


3278s/3279s. Host commun- 


communication network. Reset by 


(Model 51 C-SDLC) 


Reminder 


a. A valid frame not 
received in the past 
20-25 seconds, or 

b. The communication 
line is hung at space 
or a valid data 
character. 


ication is inhibited. 


receipt of a valid frame or a frame 
containing a poll. 


521 


Comm Chk 


No Flag characters on 


(Model 1 C-SDLC) 


or 


the line in the past 






(Model 51C-SDLC) 


Reminder 


20-25 seconds. On a 
switched network, two 
successive occurrences 
of an idle timeout will 
cause the station to 
disconnect. 






522 


Comm Chk 


The control unit Read 


(Model 51C; Multi- 


or 


Control Block over- 






Use Comm Loop) 


Reminder 


flowed. The line may 
be hung at a space or 
valid data character. 







Figure B-2 (Part 2 of 4). 3274 Communication Checks or Reminders 



Appendix B. Status Indicator Codes B-7 



Error Code 


Indicator 


Probable Cause 


Effect 


Recovery 


525 


Comm Chk 


A connection problem 


Display error indicator on all 


Verify the operational status of the 


(Model 1 C-SDLC) 


or 


exists on the commun- 


3278s/3279s. Host commun- 


communication network. 


(Model 51 C-SDLC) 


Reminder 


ications link that pre- 
vents establishing or 
reestablishing host 
communication (set 
by receipt of 20 Write 
retries, 20 ROLs, 20 
CRs, 20XIDs,or20 
NSAs). 


ication is inhibited. 




525 


Comm Chk 


Display error indicator on all 


Verify the operational status of the 


(Model 51 C; Multi- 


or 




3278s/3279s. Host commun- 


network. If the wrap tests failed, 


Use Comm Loop) 


Reminder 




ication is inhibited. The 
station is closed and wrap 
tests are performed. If the 
wrap tests fail, XN 332, 


an IML is required. If the wrap 
tests were successful, an SNRM is 
required. 










527 


Comm Chk 


Write timeout caused 


333, or 336 is broadcast. 


Verify the operational status of the 


(Model 51C; Multi- 


or 


by a clocking problem 




network and re-IML. 


Use Comm Loop) 


Reminder 


or a missing CTS. 






528 


Comm Chk 


Command Reject 


Display error indicator on all 


Host recovery (SNRM required). 


(Model 1 C-SDLC) 


or 


caused by: 


3278s/3279s. Host commun- 


Verify proper 370X parameters, if 


(Model 51C-SDLC) 


Reminder 


a. Detection of an NR 
sequence error, or 

b. Receipt of a com- 
mand that has no 
data field defined, 
or 

c. Receipt of an 
invalid command. 


ication is inhibited. 


condition persists. 


529 


Comm Chk 


Abnormal response 


Display error indicator on all 


Check modem; Host recovery 




or 


from the modem. 


3278s/3279s. Host commun- 


(SNRM required). 




Reminder 




ication is inhibited. All PUs 
and LUs are deactivated. 




530 


Comm Chk 


Write timeout caused 


Display error indicator on all 


Check modem; Host recovery. (In 


(Model 1C) 


or 


by: 


3278s/3279s. Host commun- 


SDLC, SNRM is required.) 


(Model 51C) 


Reminder 


a. Modem clocking 
missing, or 

b. CTS has dropped. 


ication is inhibited. In SDLC, 
all PUs and LUs are deactiv- 
ated. 




531 


Comm Chk 


CU has sent an NAK 


Display error indicator on the 


Host recovery. (Host should 


(Model 1C-BSC) 


or 


response because: 


affected 3278s/3279s. The 


retransmit the last transmission.) 


(Model 51C-BSC) 


Reminder 


a. A BCC error was 
detected, or 

b. Three seconds 
elapsed during a 
Read operation 
without receiving 
Syn,ETX,or 
ETB, or 

c. A forward abort 
(ENQ in text) was 
received, or 

d. A Temporary Text 
Delay sequence 
(STX ENQ) was 
received. 


terminal buffer affected is re- 
stored to its state before the 
error occurred. 





Figure B-2 (Part 3 of 4). 3274 Communication Checks or Reminders 



B-8 



Error Code 


Indicator 


Probable Cause 


Effect 


Recovery 


532 


Comm Chk 


Approximately 20 


Display error indicator on all 


Verify the operational status of the 


(Model 1C-BSC) 


or 


seconds have elapsed 


3278s/3279s. Host commun- 


communication network. Host re- 


(Model 51 C-BSC) 


Reminder 


without detecting SYN 
characters on the line. 


ication is inhibited. 


covery. (A valid Poll or Selection 
Addressing sequence is required.) 


533 


Comm Chk 


The CU did not receive 


Display error indicator on the 


Host recovery. (Host should re- 


(Model 1C-BSC) 


or 


ETX or ETB with the 


3278s/3279s. The terminal 


transmit the last transmission sent 


(Model 51 C-BSC) 


Reminder 


last block of text trans- 
mitted by the host 
system. The host sys- 
tem has sent ENQ to 
theCU. 


buffer affected is restored to 
its state before the error 
occurred. The CU will trans- 
mit its last ACK (1/0). 


that preceded ENQ.) 


534 


Comm Chk 


a. The CU did not 


Display error indicator on the 


Host recovery. (A valid Poll or 


(Model 1C-BSC) 


or 


receive a response 


affected 3278s/3279s. Host 


Selection Addressing is required.) 


(Model 51 C-BSC) 


Reminder 


to its last block 
sent, and has sent 
ENQ 15 times, 
b. The CU has 
acknowledged a 
Selection Address- 
ing sequence or a 
Text block re- 
ceived from the 
host system and 
has waited 45 sec- 
onds without de- 
tecting synchron- 
ization (PADs and 
SYNs). 


communication is inhibited. 
The CU transmits EOT. 




535 


Comm Chk 


The CU received 15 


(Model 1 C-BSC) 


or 


consecutive NAKs to 






(Model 51 C-BSC) 


Reminder 


its last transmission. 






536 


Comm Chk 


The CU received 15 


(Model 1 C-BSC) 


or 


consecutive ACKOs 






(Model 51 C-BSC) 


Reminder 


instead of ACK1s, or 
vice versa. 






551 


Comm Chk 


CU detected bad 


Display error indicator on 


Host recovery. 


(Model 1B) 


or 


parity on any command 


affected 3278/3279. 




(Model 1D) 


Reminder 


or data byte received. 


Set sense: BOC 





Figure B-2 (Part 4 of 4). 3274 Communication Checks or Reminders 



Appendix B. Status Indicator Codes B-9 



Glossary of Terms and Abbreviations 



A 

A-port. A 3274 device cable connection point for a category A 
terminal. 

A-type terminals. See category A terminals. 

ACK. A positive acknowledgment. 

ACTLU. Activate Logical Unit. 

ACTPU. Activate Physical Unit. 

alias. Alternate label. 

B 

B-port A 3274 device cable connection point for a category B 
terminal. 

B-type terminals. See category B terminals. 

BB. Begin bracket. 

BCC. Block check character. 

BETB. Between bracket. 

BOC. Bus out check. 

BSC. Binary Synchronous Communications. 



communication controller. A type of communication control 
unit whose operations are controlled by a program stored and 
executed in the unit. 

concurrent test. A test that can be run within the same time 
interval that is used for other work. 

control unit (CU). A device without programmable storage that 
controls input/output operations at one or more devices. 

control unit port. As used in this publication, the device cable 
connection point at a control unit. 

CPU. Central processing unit. 

CR. Command reject. 

CRV. Cryptography Verification. 

crypto. Encrypt/Decrypt. 

CS. Current state. 

CSW. Channel status word. 

CTS. Clear to send. 

CU. Control unit. 



category A terminals. Terminals that attach to a type A terminal 
adapter: 3278 Display Station, 3279 Color Display Station, 

3287 Printer (120 characters per second), 3289 Line Printer. 

category B terminals. Terminals that attach to a type B terminal 
adapter: 3277 Display Station; 3284, 3286, 3287 Printer; 

3288 Line Printer. 

CCA. Common communication adapter. 

CD. Change direction. 

channel. A hardware device that connects the CPU and main 
storage with the I/O control units. 

CNFG. Configure. 

communication facilities. Anything used or available for use in 
furnishing data communication service. 

communication line. Any medium, such as a wire or a telephone 
circuit, that connects a remote station with a computer. 

communication link. The physical means of connecting one 
location to another for the purpose of transmitting and receiving 
data. 



DAF. Destination address field. 

DCB. Device control block. 

DEMF. Display Exception Monitoring Facility. 

DFC. Data flow control. 

DISC. Disconnect. 

DSR. Data set ready. 

E 
EAU. Erase all unprotected. 
EB. End brackets. 

ECSA. Extended character set adapter. 
EIA. Electronic Industries Association. 
ENQ. Enquiry. 
EOT. End of transmission. 
ETB. End of transmission block. 



Glossary G-l 



ETX. End of text. 
E/W. Erase/write. 
EWA. Erase write alternate. 
EXR. Exception response. 



NPDA. Network Problem Determination Application. 
NR/NS. A receive sequence count/ send sequence count. 
NSA. Nonsequenced acknowledgment. 



FERS. Facility Error Recognition System. 
FI. Format indicator. 
FM. Field mark. 



OAF. Origin address field. 

OC. Operation check. 

Operator Information Area. The area on a display screen, below the 
horizontal line, used to display operator information. 



H 
HPCA. High-Performance Communication Adapter. 

I 
INC. In chain (state). 
I/O. Input/output. 

L 

LIC. Last in chain. 

local copy operation. An operation that copies the contents of the 
buffer from one display station or printer to another display 
station or printer attached to the same control unit. 

logged. Recorded. 

LOGON. A request by or on behalf of a terminal to be connected 
to an application program. 

LU. Logical unit. 



M 



modem. A modulator-demodulator. 

modulator-demodulator (modem). A device that modulates and 
demodulates signals transmitted over communication facilities 
(sometimes called a data set). 

MPF. Mapping field. 



N 

NAK. A negative acknowledgment. 

NCP. Network control program. 

No RTR. Not ready to receive. 

nonswitched line. A connection between a remote terminal and a 
computer that does not have to be established by dialing. 



PAD. Pad characters, generated to ensure complete transmission or 
reception of the first and last significant characters of each 
transmission. 

PDG. Problem Determination Guide. 

PIU. Path information unit. 

PLU. Primary logical unit. 

port, control unit. As used in this publication, the device cable 
connection point at a control unit. 

PU. Physical unit. 

R 

RA. Repeat to address. 
Rd. Read. 

Rd Mod. Read modified. 
RH. Request/response header. 
ROL. Request online. 
RTR. Ready to receive. 
RU. Request/response unit. 

S 
SBA. Set buffer address. 
SDLC. Synchronous Data Link Control. 
SF. Start field. 
SLU. Secondary logical unit. 
SNA. Systems Network Architecture. 
SNBU. Switched network backup. 
SNRM. Set normal response mode. 



G-2 



STX. Start of text. W 

SYN. Synchronous idle. WCC. Write control character. 

T X 

TCU. Transmission control unit. XID. Exchange station identification. 

TH. Transmission header. 

TIO. Test I/O. 

transmission control unit (TCU). An input/output control unit that 
addresses messages to and receives messages from a number of 
remote terminals. 



Glossary G-3 



Index 



basic assurance test 4-1 



cables, device 2-2, 2-3, 3-3 
checks 

communication 2-1, B-l 

machine 2-1 

program 2-1, B-l 
Communication Checks 2- 1 , B-l 
communication facility level 2-1, 2-3 
Communication Reminder 2-1, B-l 
concurrent test 4-1 
configuration, system 2-1 
control unit port 3-3 
coordinator 1-1 
cursor 2-1, 3-1 



port, control unit 3-3 
problem determination 
actions 2-3 
approach, typical 2-1 
coordination 1-1 
facilities 

host system 4-3 
3270 4-2 



3274 

3278 

3279 

3287 
introduction 
overview 2-1 
system guide 



4-1 
4-1 
4-1 
4-1 



1-1 



3-1 



Problem Determination Guide (PDG) 
Program Checks 2-1 , B-l 



1-1 



device cables 2-2, 2-3, 3-3 

display character check 4-1 

Display Exception Monitoring Facility (DEMF) 

introduction 1-1 

use 2-1,4-4 



facilities 

host system 4-3 
3270 4-2 
3274 4-1 

3278 4-1 

3279 4-1 
3287 4-1 

Facility Error Recognition System (FERS) 
introduction 1-1 
use 2-1,4-3 



host system level 2-1, 2-3 



information display system level 2-1, 2-3 
interface wrap test 4-3 



keyboard check 4-1 



level, system 2-1, 2-3 



Machine Checks 2-1 



Network Problem Determination Application (NPDA) 4-4 



Reminder, Communication 2-1, B-l 



status 

connection 4-1 

error check 4-1 

host attachment 4-3 

indicator codes B-l 

off 4-1 

on 4-1 

readiness 4-1, 4-3 

summary display A-l 

test 4-1 
symbols 

Communication Check 2-1, B-l 

Communication Reminder 2-1, B-l 

Machine Check 2-1 

Operator Information Area 2-1, B-l 

Program Check 2-1, B-l 
system configuration 2-1, 2-2 
system level 2-1,2-3 



terminal level 2-1,2-3 

terminals 2-1 

test 

basic 4-2 

basic assurance 4-1, 4-2 

concurrent 4-1 

interface wrap 4-3 

message 4-2 

offline 4-1 

online 4-1 

remote interface 4-2 

status 4-1,4-3 



Operator Information Area 2-1, B-l 



Index X-l 



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IBM 3270 

Information Display System 

Problem Determination 

Order No. GA27-287 1-2 

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